Finite-temperature behavior of an interspecies fermionic superfluid with population imbalance

We determine the superfluid transition temperature Tc and related finite temperature phase diagrams for the entire BCS-Bose-Einstein-condensation crossover in a three-dimensional homogeneous mixture of 6Li and 40K atoms with population imbalance. Our work is motivated by the recent observation of an interspecies Feshbach resonance. Pairing fluctuation effects, which significantly reduce Tc from the onset temperature for pairing (T*), provide reasonable estimates of Tc and indicate that the interspecies superfluid phase should be accessible in future experiments. Although a homogeneous polarized superfluid is not stable in the ground state near unitarity, our phase diagrams show that it stabilizes at finite temperature.